The present invention relates generally to the field of foundry processing, and more particularly to heat treating metal castings and reclaiming sand from sand cores and sand molds used in the manufacture of metal castings.
Many changes have been made in the field of heat treating of metal castings and reclaiming sand from sand cores and sand molds used in the manufacture of metal castings. Examples of some recent disclosures which address the heat treating of castings, removal of sand cores, and further reclaiming of sand are found in U.S. Pat. Nos. 5,294,094, 5,354,038, 5,423,370, and 5,829,509 (hereinafter sometimes referred to collectively as the xe2x80x9cReference Patentsxe2x80x9d), each of which is expressly incorporated herein by reference, in their entirety. Those patents disclose a three-in-one process/integrated system that (i) receives and heat treats a casting, (ii) removes sand core/sand mold materials from the casting, and (iii) reclaims sand from the sand core/sand mold materials removed from the casting; the ""094 and ""038 patents embodying a convection furnace species, the ""370 patent embodying a conduction furnace species, and the ""509 patent alternately embodying either a conduction furnace species or a convection furnace species (and adding an integrated cooling chamber). The sand core/sand mold materials (referred to hereafter as sand core materials) comprise sand that is held together by a binder material such as, but not limited to, a combustible organic resin binder.
Technology such as that disclosed in the above-mentioned patents are driven, for example, by: competition; increasing costs of raw materials, energy, labor, and waste disposal; and environmental regulations. Those factors continue to mandate improvements in the field of heat treating and sand reclamation.
Briefly described, the present invention provides a single furnace system which integrates, in combination, a plurality of distinct heating environments (which in the preferred embodiments include two heating environments comprising a conduction heating environment and a convection heating environment) integrated such that the plurality of environments define a continuous heating chamber through which a moving workpiece (such as a casting) transitions from one heating environment to the other without being exposed to the atmosphere. In accordance with the preferred methods, the transitioning of the casting from one environment to the other is accomplished with no meaningful change in temperature.
In accordance with a second aspect of the invention, improved species embodiments of a 3-in-1 processing system of the genus described in the above identified prior patent specifications are provided. These species embodiments of the present invention disclose a system apparatus and method for processing a casting which perform the integrated processes of core removal, sand reclaiming and heat treatment in a combination conduction and convection furnace system.